Bhagavad Gita Bhasya (Gambhirananada)

nonperception, as their beginning (adi) are
avyaktaadini. Ca, and; after origination, before
death, they become vyakta-madhyani, manifest in
the middle. Again, they eva, certainly; become
avyakta-nidhanani, unmanifest after death. Those
which have unmanifestness (avyakta), invisibility,
as their death (nidhana) are avyakta-nidhanani.
The idea is that even after death they verily attain
unmanifestedness. Accordingly has it been said:
'They emerged from invisibility, and have gone
back to invisibility. They are not yours, nor are you
theirs. What is this fruitless lamentation!' (Mbh. St.
2.13). Ka, what; paridevana, lamentation, or what
prattle, can there be; tatra, with regard to them, i.e.
with regard to beings which are objects of
delusion, which are invisible, (become) visible,
(and then) get destroyed!
2.29 Someone visualizes It as a wonder; and
similarly indeed, someone else talks of It as a
wonder; and someone else hears of It as a wonder.
And some one else, indeed, does not realize It even
after hearing about It.
English Translation of Sri Sankaracharya's Sanskrit
Commentary - Swami Gambhirananda
51